Bulkhead for a motor vehicle

ABSTRACT

An end wall for a motor vehicle may include: a first wall as well as a second wall distanced thereto, a foam arranged between the first and second wall, an allocated first opening arranged in the first wall, an allocated second opening in the second wall for leading through a through-body penetrating the openings, wherein the foam at least in regions bears on the through-body, a peripheral gap is arranged between the through-body as well as the first and/or second wall in the region of the allocated openings, the foam comprises a foam opening for leading through the through-body, the foam opening—when the through-body has not been introduced, at least in regions—has a smaller diameter than the through-body.

BACKGROUND

The present invention relates to an end wall (also known as “front wall”or as “bulk head”) for a motor vehicle.

An end wall for a motor vehicle is known in principle. With this, it isthe case of a separating wall between the motor space and the vehiclepassenger space. The end wall fulfils various tasks. On the one hand itsserves for the stability of the car body (e.g. against torsion about thelongitudinal axis of the vehicle), on the other hand it serves e.g. forcrash safety (against penetration of components from the motor spaceinto the vehicle interior with a frontal collision). Furthermore itserves for the thermal as well as sound insulation between the motorspace and vehicle interior.

End walls may have a “sandwich construction”. Here, the end wallcomprises a first wall as well as a second wall distanced to this, andfoam is arranged between the first and second wall.

But often there exists the necessity to create connections from themotor space to the motor vehicle interior and for this to provideopenings in the end wall. These may e.g. be openings for leading througha longitudinal rod or for leading through supply ducts of the airconditioning installation, etc.

For this, the end wall usually comprises openings which e.g. areprovided with a radial rubber seal. The rubber seal at the same time hasthe task of sealing a through-body led through openings of the end wall,in the region of the first and second wall, in that the rubber sealsuitably bears on the through-body. At least the transfer of airbornesound as well as the entry of moisture from the motor space into thevehicle interior may be prevented by way of this.

The disadvantage with this however is the fact that the adaptation andassembly of this rubber seal is quite costintensive. Added to this isthe fact that the rubber seal only offers a limited tolerancecompensation so that on the one hand it is possible that with a rubberseal which is too tight, a damage to the rubber seal on leading throughthe through-body occurs. On the other hand it is quite possible that ifthe rubber seal is selected too large, a residual gap remains, and byway of this the entry of moisture or the transfer of airborne sound intothe vehicle interior becomes possible.

It is therefore the object of the present invention to create an endwall which on the one hand may be manufactured in an economical mannerand on the other and prevents the passage of moisture or sound from themotor space to the vehicle interior to an as large extent as possible.

SUMMARY OF THE INVENTION

This object is achieved by an end wall according to claim 1.

This specifies an end wall for a motor vehicle, wherein the end wallcomprises a first wall as well as a second wall distanced to this, and afoam is arranged between the first and the second wall. An allocatedfirst opening is arranged in the first wall, and an allocated secondopening is arranged in the second wall, for leading through athrough-body which penetrates the openings. The foam at least in regionsbears on the through-body. A peripheral gap is arranged in the region ofthe allocated openings, between the through-body as well as the firstand/or second wall. This gap may either be an air gap or may be filledwith foam. It is important however that no direct contact is givenbetween the first or the second wall and the through-body.

Such an end wall has the advantage that a direct contact between thethrough-body and the first or second wall is prevented and thus astructure-borne sound transfer from the through-body to the first orsecond wall (which thus represent the outer walls of the “sandwich”) isavoided. The foam which reaches up to the through-body at the same timeprevents the passage of airborne sound from the motor space into thevehicle interior. Furthermore a barrier against the passage of moistureis rendered possible by way of the foam.

At the same time it is particularly advantageous that no additionalsealing elements such as radial rubber seals need to be used forsealing. The assembly effort is reduced by way of this. The foam whichis present in any case in the sandwich serves for sealing. This foamthus apart from having a sound-insulating or stabilising effectadditionally has the effect that it carries the through-body orinsulates the penetration location with regard to sound and moisture.

Here several variants for manufacturing the end wall are possible. Onthe one hand it is possible for the through-body itself to be“foamed-in” on manufacture of the end wall. Depending on the nature ofthe foam or the surface of the through-body (this may be coated e.g.with Teflon), there then results a firm connection between the foam andthe through-body, or also no firm connection. In a further variant it ispossible for the through-body of not being in its final position onfoaming out the sandwich construction. Here e.g. it is possible by wayof a suitable moulding tool or by way of the provision of a sleeve (tobe removed later) to create a foam opening for a through-body to beintroduced later.

Advantageous designs of the present invention are specified in thedependent claims.

One advantageous design envisages the foam to be polyurethane foam. Thishas the advantage that a foaming which fills the inner space isparticularly simply possible. It is of course possible to attachpremanufactured foam sections in the intermediate space between firstand second wall.

A further advantageous design envisages the first and/or second wallbeing of metal or plastic and having a wall thickness between 0.6 mm and6 mm. Here the modulus of elasticity of the material should be as highas possible. What is decisive is the modulus of elasticity of thecomplete composite of walls and foam lying therebetween. However herethe weight of the design must also be taken into account.

One particularly advantageous design envisages the foam being profiledin the contact region to the through-body. Here the foam e.g. withregard to its profile may have a wave structure which only contacts thethrough-body in regions. By way of this an even simpler introduction ofthe through-body is possible since the friction resistance is smaller onintroduction. Despite this, in the region of the “wave hills”, thus inthe contact region between the foam and the through-body one may achievea particularly high pressing pressure which thus may reliably prevent atransfer of airborne sound. For manufacturing such a wave structure itis e.g. possible to use a mandrel on foaming with polyurethane, which ise.g. coated with Teflon and may be removed again from the foam after thefoaming process.

A further advantageous design envisages the foam in the region at leastof one opening, e.g. the first opening, to terminate essentially flushwith the allocated wall (thus the first wall) on the side which isdistant to the opposite wall (thus the second wall). I.e. that the endwall at its outer sides terminates with the foam in a practically flatmanner. Of course it is also possible for the foam to be set backinwards with respect to the outer sides of the end wall so that an airgap remains between the through-body and the first or second opening inthe region of the first or second opening.

Furthermore one advantageous design envisages the foam in the region ofthe opening, e.g. the first opening, to project beyond the allocatedwall (thus the first wall) to the side which is distant from theopposite wall. This in practise means that the foam projects laterallyout of the sandwich structure of the end wall. An even better supporteffect for penetration bodies which are led through is achieved by wayof this. Furthermore, the transmission of structure-borne sound from thethrough-body directly to the first or second wall is prevented in aneven more secure manner. Furthermore an even better airborne soundinsulation is possible by way of the longer foam lengths along thethrough-body. An even better tolerance compensation is particularlyadvantageous since the flexible foam along the complete length of thethrough-body may bear on this and thus a transfer of airborne sound isprevented in an even more secure manner.

One further advantageous design envisages the through-body e.g. to beround and a diameter between. With this it may be the case e.g. of asteering rod etc. rotatable relative to the foam. It is however alsopossible for it to be the case of an aluminium tube which fortransmitting fluids (e.g. for the air conditioning installation) extendsfrom the motor space to the motor vehicle interior.

A further design envisages the through-body to be designed as a sleevefor leading through rods, cables or likewise. It is indeed advantageousfor the through-body to be formed itself e.g. by way a tube conduit andto have direct contact with the foam. The variant of the through-body asa sleeve for leading through rods etc. however is possible for cases inwhich a relative movement e.g. of a rod to the foam which wouldotherwise be too large is given.

A further advantageous further formation envisages the gap between thethrough-body and the wall in the region of the allocated opening to bebetween 5 mm and 20 mm. By way of this it is ensured that even with avibrating end wall, a structure-borne sound transmission by way ofcontacting the through-body as well as the first or second wall isprevented.

A further advantageous design envisages one wall, e.g. the first wall,in the region of the allocated first opening to be inwardly curved tothe side which is distant to the respective opposite wall (thus here thesecond wall). This in practise means that a vaulting of the end wall tothe outside is given. By way of this, in particular with an obliquepassage of the through-body through the sandwich, an even longercarrying (support) length of the through-body in the foam is renderedpossible. Apart from an improved stability, here an even better acousticdamping and a correspondingly good tolerance compensation are ensured.

A further advantageous design envisages one wall, i.e. the first wall,if this represents the wall on the motor space side, to comprise anadditional sealing lip in the region of the associated first opening forembracing the through-body. An effective spray protection may be ensuredby way of this. Multiple seals are also possible.

A further particularly advantageous design envisages the foam tocomprises a foam opening for leading through the through-body, whereinthe foam opening, when the through-body has not been introduced, atleast in regions has a smaller diameter than the through-body. By way ofthis one succeeds in achieving an even better sound-insulation as wellas moisture sealing effect by way of the pressing pressure of the foamon the through-body. For a simplified assembly one may envisage the foamopening being narrowed in the course of the assembly direction of thethrough-body, so that an even simpler assembly is achieved (with a lowas possible damage to the foam).

Further advantageous designs of the present invention are specified inthe remaining dependent claims.

BRIEF DESCRIPTION OF THE DRAWING

The invention is now explained by way of several Figures. There areshown in:

FIG. 1 a first cut-out of an end wall according to the invention, with athrough-body arranged therein,

FIG. 2 a second cut-out of the end wall according to the invention, witha further through-body arranged therein.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an end wall 1 for a motor vehicle. The end wall comprises afirst wall 2 a as well as a second wall 2 b distanced to this. Foam 3 isarranged between the first and second wall. The first wall 2 a comprisesan allocated first opening 4 a and the second wall 2 b comprises anallocated second opening 4 b. A through-body 5 penetrates the firstopening 4 a as well as the opening 4 b which is flush with this. Thefoam 3 at the same time bears on the through-body 5, it embraces itcylindrically in FIG. 1.

A gap 6 a filled with foam is arranged between the through-body 5 aswell as the first opening 4 a.

In the region of the second opening 4 b between the through-body 5 aswell as the second wall there is provided a peripheral gap 6 b filledwith foam, which is likewise filled out with foam.

The foam is of polyurethane; the first wall 2 a as well as the secondwall 2 b are in each case of plastic. The introductory description isreferred to with regard to details of geometry and material.

The gap 6 a and 6 b have an extension of 4 mm to 35 mm, 5 mm to 20 mmare also possible (see dimension arrows in FIG. 1).

The through-body 5 is an aluminium tube which represents aconnection/evaporator/heat exchanger and thus e.g. transportscondensation water of the air conditioning installation between thepassenger space and the motor space. A round, oval, polygonal etc.cross-sectional shape is possible for all penetration bodies 5 accordingto this invention. On account of safety regulations it is necessary forthis material to be constructed of such a stable material as aluminium.It is particularly here that the advantageous nature of the presentinvention comes in, since with a contact of the first wall 2 a or secondwall 2 b with the through-body 5, a heavy transmission ofstructure-borne sound would occur. Therefore a correspondingtransmission of structure-borne sound is minimised by the intermediatefoam. Additionally, for reducing vibrations transmitted to the aluminiumtube, a part of this aluminium tube is covered by way of a suitableplastic hose in the motor space.

A particularly good leading of the through-body 5 as well as aparticularly secure protection of the structure-borne sound transmissionfrom the through-body 5 to the first wall 2 a or second wall 2 b isachieved in that the foam on the outer sides of the end wall 1 projectbeyond the first and second wall in each case on the outer sides. Anadequate guiding (lead) length of the foam to the through-body 5 isachieved by way of this, by which means on the one hand a good sealingeffect is achieved and on the other hand a stable guiding is achieved.

The foam 3 has been foamed from polyurethane foam, the foam opening forleading through the through-body 5 here was kept free by way of asuitable Teflon-coated mandrel which was removed after the foaming [out]procedure.

For an improved illustration of the context, the (uniform) diameter 9 ofthe through-body 5 is shown in FIG. 1. The diameter of the foam openingis indicated with a dashed line. “Foam opening” is the opening in thefoam caused by the mandrel, into which the through-body 5 was introducedin the direction z. Here the diameter of the foam opening is indicatedin the entry side at 8.1. This diameter reduces in the assemblydirection z to the measure 8.2. By way of the reduced dimension of thefoam opening with respect to the diameter of the through-body 5, a firmbearing of the foam on the through-body and thus a good airborne soundinsulation as well as moisture barrier is ensured.

On the upper side of the end wall shown in FIG. 1, a protective layer 10is attached on the first wall 2 a or the projecting part of the foam 3.Here it may e.g. be the case of an aluminium layer which is vapourdeposited and which prevents an electrical charging of parts of the wallor of the through-body. Alternatively here a plastic film etc. may beattached for an even better sealing from the entry of fluid.

FIG. 2 shows another section of the end wall 1. All of theabove-described features (of FIG. 1 as well as the introductorydescription) also apply to the description of FIG. 2 inasmuch as is notexpressly stated otherwise. With the through-body shown in FIG. 2 it isthe case of a steering rod 5′ which is rotatable about its longitudinalaxis. The foam 3 which is arranged between the first wall 2 a and thesecond wall 2 a projects in the region of the first opening 4 a′ beyondthis opening. In the region of the second wall 2 b the foam does notproject into the opening 4 b′ of the wall 2 b, so that in the region ofthe opening 4 b′ only an air gap between the through-body 5′ and theadjacent wall 2 b is given.

The walls in FIG. 2 in each case are curved outwardly in the region ofthe first opening 4 a′ as well as in the region of the second opening 4b′. By way of this a larger guide length of the foam 3 results for thethrough-body 5′.

In contrast to FIG. 1, the foam 3 in the contact region with thethrough-body 5′ is profiled in cross section. I.e. that along thelongitudinal axis of the through-body 5′ the foam comprisesconstrictions at a distance. A contact of foam and through-body is givenin the region of these constrictions. By way of this a simpler rotationof the through-body 5′ is achieved since one needs to overcome lessfrictional work. An additional sleeve with a rubber lip 7 which offer aspray protection from fluid is connected in front of the foam in theregion of the first opening 4′.

The present invention thus describes an end wall for a motor vehicle,wherein the end wall comprises a first wall as well as a second walldistanced to this, and a foam is arranged between the first wall and thesecond wall, and an allocated first opening is arranged in the firstwall and an allocated second opening in the second wall, for leadingthrough a through-body, wherein the same foam which is arranged in aflat (large-surfaced) manner between the first and second wall, at leastin regions, bears on the through-body, and a peripheral gap is arrangedbetween the through-body as well as the first and/or second wall in theregion of the allocated openings. The advantages according to theinvention are in particular also achieved due to the fact that one andthe same foam is used for the end wall insulation as well as for thecontact of the through-body. With the end wall shown in the presentinvention it is not the case of a separate end wall insulation, but of atwo-walled end wall in a sandwich construction which consists of twocover layers which are foamed to one another. The basic idea at the sametime is the simultaneous foaming of a sealing collar so that no separatepart (such as bloated foam insert) is necessary. Thus one requires notype of joining of such a separate sealing collar.

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 13. An end wall for a motor vehicle,comprising: a first wall having an allocated first opening arrangedtherein; a second wall distanced from the first wall and having anallocated second opening therein; a through-body extending through thefirst and second openings and defining peripheral gaps between thethrough body and the respective first and second openings; foam arrangedbetween the first and second walls, which foam bears on at least someregions of the through-body and is disposed in the peripheral gaps, andwhich foam comprises a foam opening for accommodating the through-bodythat has a smaller diameter than the through-body in at least someregions when the through-body is not present.
 14. The end wall accordingto claim 13, wherein the foam is a polyurethane foam.
 15. The end wallaccording to claim 13, wherein the first and/or second wall is formed ofmetal or plastic and has a wall thickness of between about 1 mm andabout 30 mm.
 16. The end wall according to claim 13, wherein the foamopening includes a profile in a region of contact with the through-body.17. The end wall according to claim 13, wherein the foam in the regionof at least one of the first and second openings terminates essentiallyflush with the first or second wall allocated therewith on a sidedistant to the opposite wall.
 18. The end wall according claim 13,wherein the foam in the region of the first opening projects beyond thefirst wall to a side distant to the opposite second wall.
 19. The endwall according to claim 13, wherein the through-body is one ofsubstantially round, oval or polygonal, in cross section.
 20. The endwall according to claim 13, wherein the through-body is designed as asleeve for leading through rods, cables, wires or the like.
 21. The endwall according to claim 13, wherein the peripheral gaps between thethrough-body and first and/or second walls in the region of therespective first and/or second openings is between about 4 mm and about35 mm.
 22. The end wall according to claim 13, wherein the first wall inthe region of the allocated first opening is curved to the side which isdistant to the respective opposite second wall.
 23. The end wallaccording to claim 13, wherein at least one of the first and secondwalls in the region(s) of the respective associated first and secondopenings comprises an sealing lip.
 24. The end wall according to claim23, wherein the diameter of the foam opening tapers in a longitudinaldirection of the through-body.